How to Feed Electrolytes to Horses

We recently had a horse owner ask about providing electrolytes to her horses all at once, through the watering trough.  While in theory this might work, in practicality, it may cause some issues.

First, it is important to understand what horses need:

• The key electrolytes are sodium, chloride, potassium and magnesium.
• Forages and feed normally contain adequate potassium and magnesium to maintain body levels.

Then, we need to understand how a horse consumes & utilizes electrolytes:

• The best way to add these to a horse’s diet is to provide free choice salt in a loose form at all times, as sodium and chloride are the primary electrolytes lost in sweat.
• Horses may not consume enough salt if the salt is in block form, particularly during cold weather or hot, humid conditions.
• Horses cannot store excess electrolytes and will excrete in the urine.

If you have particular events where the horses will be worked hard, particularly in hot, humid conditions, it is recommended to provide the additional electrolytes immediately prior to, during and immediately following a competition.  Maintaining water consumption is key to preventing dehydration and adding electrolytes to the water may not be desired.

Dr. Krishona Martinson at the University of Minnesota recently published a useful newsletter review that suggested that adding supplements to the drinking water for horses can actually decrease water consumption, which is exactly what you would want to avoid doing.